DNA中糖苷键碱基侧二共价键的喇曼特性分析

On the Raman Characteristics of Covalent Bonds Flanked to the Glycoside Bond in DNA Purine Base

分析小牛胸腺ＤＮＡ的纤维和水溶液两种状态样品的激光喇曼光谱发现，嘌呤碱基糖苷键两侧共价键Ｎ９Ｃ４与Ｎ９Ｃ８的喇曼特性表现不同，分析与它们相联的Ｎ３与Ｎ７原子在原子电荷、一级水合层中水桥的形成，以及核苷酸单位内氢键形成等方面的差异，可认为在ＤＮＡ水溶液中Ｎ９Ｃ４明显的减色性是因Ｎ３原子的特殊性质所造成。

The Raman characteristic difference between the two covalent bonds N9C4 and N9C3 flanked to a glycosidic bond in the purine base of calf thymus NDA has been studied by laser Raman spectroscopy both in the fibrous state and in aqueous solutions. The difference can be attributed to the distinction of N3 and N7 adjacent to the above-mentioned two covalent bonds. The difference comes from their distinct partial atomic charges, water bridge formation in the primary hydration shell and intramolecular hydrogen bond formation in the nucleotides. The N9C4 Raman hypochromicity in DNA aqueous solutions can be explained by the unique nature of N3 atom.